A comparison of histological changes induced by Xiphinema basiri and X. ifacolum in the roots of tomato

T. Bleve-Zacheo, G. Zacheo, C. E. Taylor


Xiphinema ifacolum and Xiphinema basiri fed on the root tip of tomato, and as a result the tips were transformed into galls. Sections of galls incited by X. ifacolum revealed a column of necrotic cortical cells, penetrated by the odontostyle and representing the feeding site. Nematode feeding caused hypertrophy of the cells, which had cytoplasm packed with inclusions, and nuclei and nucleoli larger than those of unaffected cells. Cell wall stubs were present in cells with more than one nucleus, indicating that there were mitoses with failed cytokineses. These modifications are very similar to those induced by x. index in its host. Feeding of x. basiri induced a drastic disturbance of the physiology of the root tips, which were transformed into galls. All of the procambial tissue was transformed to a cisternum (Iysigenous cavity) without cytological structures probably caused by the injection of lytic enzymes by the nematode and their diffusion within the root. Nuclei in the meristematic cells far from the feeding site were stopped in interphase and the structure of their components indicated they had lost the capacity of synthesis.

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